Oaks of the World

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  Quercus polymorpha
Author Schltdl. & Cham. 1830 Linnaea 5: 78
Synonyms guatimalensis A.DC 1864 pro parte
petiolearis Benth. 1840
turbinata Liebm. 1854, nom. illeg. not Bl. 1825 Diagnosis here
varians Mart. & Gal. 1843
germana var. lemmonii Trel. 1924
polymorpha f. angustifolia C.H.Muller 1936
Local names net-leaf white oak ; mexican white oak ; Monterrey white oak ;
Range Mexico, on Atlantic slope (Chiapas, Hidalgo, Nuevo Leon, Oaxaca, Puebla, Queretaro, San Luis Potosi, Tamaulipas, Veracruz); Guatemala; SW Texas; 200-2450 m;
Growth habit 10-20 m tall; trunk to 50 cm wide;
Leaves 5-14 x 3-6 cm; sub-evergreen; coriaceous; elliptic or ovate; apex obtuse, rounded or retuse, seldom acuminate, mucronate; base rounded or cordate; margin thickened, slightly revolute, somewhat cartilaginous, entire or with 2-5 pairs of short, mucronate teeth; green or glaucous, slightly lustrous, almost hairless above or with stellate hairs on midvein; paler, dull, glaucous beneath, hairless or sometimes loosely fascicled pubescent, and with rusty glandular hairs scattered, mainly along veins; 8-13 vein pairs, impressed above and prominent beneath; tertiary veins conspicuous beneath; epidermis glaucous, waxy, papillose; petiole slender, yellowish, 1.4-3 cm long, glabrescent;
Flowers in March; staminate carkins 3-7 cm long, densely flowered, tomentose; pistillate flowers 1-2 on a pubescent peduncle less than 1 cm long;

acorn 1.5-1.8 cm long, 0.8-1.2 cm in diameter, oblong; singly or paired on a 1-2 cm long peduncle located at the axil of the leaves; enclosed 1/2 by cup; cup velutinous, 1.2-1.5 cm in diameter, with strongly tuberculate triangular scales; cotyledons free; maturing in 1 year from October to December;

Bark, twigs and

bark grey brown, scaly; twigs 2-3 mm wide, red brown, tomentose at first, becoming glabrous, with numerous lenticels; buds red brown, ovoid, pointed, 3-7 mm long; stipules pubescent, persistent around terminal buds, 10-13 mm long;
Hardiness zone, habitat hardy : zone 7 (hardly withstands -16° C); all types of soil; cultivated in Spain, and in UK (at Kew);
Miscellaneous -- A. Camus : n° 210;
-- Sub-genus Quercus, Section Quercus, Series Polymorphae;
-- Discovered in 1992 only in the US Territory;

-- Possible confusion with Q. germana which has petioles 0.3-0.6 cm long, acorns 2.8-4 cm long on a peduncle located at the end of the twigs.

Subspecies and
-- Q.juergensenii Liebm.1854 Overs. Kongel. Danske Vidensk. Selsk. Forh. Medlemmers Arbeider 1854: 188 (A. Camus : n° 211) Diagnosis here
from Mexico (Puebla), is a doubtful species, probably identical to Q.polymorpha, with petiole shorter and leaf base cuneate; for today's Mexican Authors (Susana Valencia-A., 2004), this species is not currently valid ; it may be a hybrid, or a morphological variety...